<template>
  <div>
    <router-link class="header-abs" to="/" v-show="isShowAbs">
      <div class="iconfont header-abs-back">&#xe623;</div>
    </router-link>
    <div class="header-fixed" v-show="!isShowAbs" :style="opacityStyle">
      <router-link to="/">
        <div class="iconfont header-fixed-back">&#xe623;</div>
      </router-link>
      东部华侨城茵特拉根温泉
    </div>
  </div>
</template>

<script>
export default {
  name: 'CityHeader',
  data () {
    return {
      isShowAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop || document.body.scrollTop
      if (top > 60) {

        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = {opacity}
        this.isShowAbs = false
      } else {
        this.isShowAbs = true
      }
    }
  },
  mounted () {
    // 因为注册的是全局事件，切换到其他页面时也会执行
    window.addEventListener('scroll',this.handleScroll)
  },
  unmounted () {
    // 页面离开时，对全局事件解绑
    window.removeEventListener('scroll',this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
  @import "~styles/variable.styl"

  .header-abs
    position: absolute
    left: .2rem
    top: .2rem
    width: .8rem
    height: .8rem
    line-height: .8rem
    border-radius: .4rem
    text-align: center
    background: rgba(0,0,0,.8)
    .header-abs-back
      color: #fff
      font-size: .4rem
  .header-fixed
    z-index: 2
    position: fixed
    top: 0
    left: 0
    right: 0
    height: $height
    line-height: $height
    text-align: center
    color: #fff
    background: $bgColor
    font-size: .32rem
    .header-fixed-back
      position: absolute
      top: 0
      left: 0
      width: .64rem
      text-align: center
      font-size: .4rem
      color: #fff
</style>
